Influence of small miscuts on self-ordered growth of Ge nanoislands

Using high-resolution X-ray diffraction (HRXRD), we have investigated lateral ordering the nanoislands formed from Ge wetting layer of various thicknesses deposited on a strained Si₁₋xGex sublayer. We observed that the high lateral ordering degree is initiated by ordered modulation of non-uniform deformation fields. This modulation is induced by small (∼0.3°) misorientation of Si substrate from [001] direction. Finally, we show that the miscut can be the source of perfectly ordered nanoisland arrays in two dimensions when the growth is performed on the strained SiGe (001) sublayer. The effect of substrate miscut can be amplified tuning the deviation of buffer layer surface from [001] growth direction via increasing the Ge content

Ebola virus disease and children

Ebola virus disease — natural focal, extremely dangerous infection with severe course characterized by fever, hemorrhagic syndrome and multiple damage to vital organs and body systems. The article describes the epidemiological situation related with the registration of cases, provides the characteristics of the pathogen, mechanisms of development, peculiarities of disease in children. Methods of the treatment and prevention of this disease are described from the modern point of view

Internal strains and crystal structure of the layers in AlGaN/GaN heterostructures grown on sapphire substrate

In this paper, we investigate the structural properties of AlGaN/GaN heterostructures grown by metal organic chemical vapor deposition on sapphire substrates with different thicknesses using high-resolution x-ray diffraction and Raman scattering methods. We discuss the microscopic nature of spatial-inhomogeneous deformations and dislocation density in the structures. Microdeformations within mosaic blocks and the sizes of regions of coherent diffraction are determined. We reveal a gradient depth distribution of deformations in the mosaic structure of nitride layers, as well as at the interface regions of the sapphire substrate on the microscale level using confocal micro-Raman spectroscopy. We determine that an increase in substrate thickness leads to a reduction in dislocation density in the layers and an increase in the elastic deformations. The features of the block structure of nitrides layers are shown to have a significant influence on their elastic properties